Portable film developing tank

ABSTRACT

A portable film developing tank which can be utilized for daylight developing having a housing for the reception of developing fluid and a helical channel therein progressing from an outside channel adjacent a feeding spool toward the center thereof with a continuous widening of the channel toward the center for reducing friction as the film is payed out or, in another embodiment, having a film cassette mounting space in the center thereof with a gradually widening helical channel progressing toward the outside of the housing; a sealable cover on top of the housing and a sealable door for access to a film cassette therein.

United States Patent Smith [54] PORTABLE FILM DEVELOPING TANK [72] Inventor: George S. Smith, 4118 Fourth Avenue, San Diego, Calif. 92103 [22] Filed: Mar. 18, 1969 [21] Appl. No.: 808,150

[4 Feb. 15, 1972 Primary Examiner-John M. Horan Assistant Examiner-Monroe H. Hayes Attorney-Carl R. Brown [57] ABSTRACT A portable film developing tank which can be utilized for daylight developing having a housing for the reception of developing fluid and a helical channel therein progre$ing [52] U.S. Cl ..95/90.5 from an outside channel adjacent a feeding spool toward the 111!- 0311 center thereof with a continuous widening of the channel [58] Field 01 Search ..95/90.5 toward the center for reducing friction as the film is payed out or, in another embodiment, having a film cassette mounting Reielemes Cited space in the center thereof with a gradually widening helical channel progressing toward the outside of the housing; a seala- UNITED STATES PATENTS ble cover on top of the housing and a scalable door for access 1,212,498 1/1917 Kelsay ..95/90.5 to a film cassette h 1,352,109 9/1920 Beidler ..95/90.5 2,076,070 4/1937 Dazey ..95/90.s 3 Glam 4 Dmwmg gums FOREIGN PATENTS 0R APPLICATIONS 7,204 3/1912 Great Britain ..95/90.5

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GEORGE 5. SMITH PORTABLE FILM DEVELOPING TANK BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a portable film developing tank and more particularly to a portable film developing tank for developing film in situ without a dark room.

According to the invention, a-portable film developing tank is provided which, preferably, has an opaque housing for daylight developing. Inside the housing, a helical channel is provided for the unwinding of a film cassette and consequent spreading of the film; the entire housing being filled with a developing fluid. In one embodiment, the film is payed out from the outside of the case inwardly toward the center with the channels progressively widening as the film moves toward the center for decreased friction. In another embodiment, the film is started from the center unwinding outwardly through the helical channel, in this case, widening as they reach the outside of the housing. Scalable covers and doors are provided for access to the developed film and the cassette. The channels are dimensioned for accepting a lengthening strip of film on one side as the film slidably moves along another side. The channel portion of the tank can be constructed as a drum or reel in cartridge form for easy removal after draining developing fluid from the housing.

An object of the present invention is the provision of a portable film developing tank which can be utilized for daylight developing.

Another object of the invention is the provision of a portable film developing tank which spreads the film in a folded helical manner in the developing fluid.

A further object of the invention is the provision of a portable film developing tank which spreads the film from the center ofa helical path outwardly.

Yet another object of the present invention is the provision of a portable film developing tank which spreads the film from the outside periphery of a helical path toward the center thereof.

A still further object of the present invention is the provision of a portable daylight film developing tank which is inexpensive to manufacture and extremely simple to operate.

Another object of the present invention is the provision of a portable daylight film developing tank in which the film can be removed in a cartridge drum.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the FIGS. thereof and wherein:

FIG. 1 is a top view of one embodiment of the present invention illustrating the film in various stages of dispersement;

FIG. 2 is a side elevation taken along sections 2A-2A and 2B2B ofFIG. 1; and

FIG. 3 is a top view of a second embodiment of the present invention; and

FIG. 4 is an exploded perspective view of a cartridge drum in spatial relationship with the tank housing.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1, the portable film developing tank is shown generally at 11 with an outside casing 12 having a side opening 13. Opening 13 has a sealable cover disposed for hermetically sealing this opening. A film cassette 16 is mounted in proximity to sprocket 17 which carries the film indicated by the dotted line l8around the sprocket l7 and between a pair of holding members 70. Various positions of the film 70 are indicatcd by loops a, b, c, d, e and f, which indicate the films passage through helical channel 19 which is defined by a helical divider wall 21. Helical channel 19 continually widens as it approaches the center portion of the developer. A circular wall 22 is provided in the center portion as a light trap for the developer.

Referring to FIG. 2, the developing tank is again shown generally at 11 having a housing 12 with a removable cover 15. The sealable side cover 14 (FIG. 1) is shown removed exposing cassette 16 and sprocket 17 which is rotated by a handle 20. The film is indicated by vertical dotted lines 18 which are separated by helical divider walls 21. The cover is kept in place by wing nut 25 in conjunction with screw 26 and sleeve 27 Referring to FIG. 3, another embodiment is shown generally at 31 having a housing 32 with its top removed. Cassette 33 feeds film, shown as dotted lines 34, around idler wheel 36 and sprocket 37 to a holding slot 38. As the film is unreeled. it is shown in payed out positions a, b, c, d, e and f by the dotted lines.

Referring to FIG. 4, a modification is shown in which a tank portion 41 is shown in spatial relationship with a cartridge drum 42. Cartridge drum 42 has a top portion 43 and a bottom portion 44 connected together with a plurality of strut members 46. Top portion 43 and bottom portion 44 have cooperating raised helical guides for forming a helical channel as shown in FIG. 3.

OPERATION Referring back to FIGS. 1 and 2, it can be seen that by removing sealable cover 14, a cassette 16 may be placed within housing 12 having an axle fitting within recess 28. The film 18 can then be threaded through and around sprocket l7 and into retaining members 70. As sprocket 17 is rotated in a clockwise direction, the film 18 will be pulled out of cassette l6 and forced along channel 19 defined by protrusions 21 from the bottom of housing 12 and the top of cover 15. As the film travels along helical channel 19, as indicated by loops 0, b, c, d, e and f, the channel continuously widens which reduces the resistance to the travel of the film due to the widening of the loop itself. After the film has been in the tank (and the developing fluid) for a proper length of time, the cover is then removed along with the film for drying. If desired, the cassette portion of the housing could be constructed in cartridge form, which would ease in loading and unloading the cassette.

Referring back to FIG. 3, the cassette 33 carries film 34 which is wound around idler wheel 36 and sprocket 37 into retaining members 38 after which, upon rotating sprocket 37 in a clockwise direction, the film is dispersed throughout the channel 39 as indicated by loops a, b, c, d, e andf. As previously mentioned, the channel 39 continuously widens toward the outside of its helical path resulting in a lessening of resistance to the movement of the film.

The cassettes can be installed for forcing the film against its natural curl or with it, depending upon the length and type of film being developed.

Referring to FIG. 4, a modification of FIG. 3 is shown wherein drum 42 contains the helical channel which is removable in cartridge form from tank 41. Film 34 is shown in a payed out position. With this modification, one drum can be removed (and utilized as a drying rack, if desired) and another inserted for substantially simultaneous developing.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

The invention claimed is: l. A portable film developing tank comprising: a housing adapted to be filled with developing fluid, mounting means within said housing for rotatably mounting a film cassette,

a helical channel within said housing,

said helical channel continuously increasing in width from one end to the other in a direction away from said mounting means,

said mounting means is located toward a center portion of said portable film developing tank and said film is payed out toward the outside of said tank. 3. The portable film developing tank of claim 1 wherein: said mounting means is located toward an outside periphery of the portable film developing tank for paying out said film toward the center of said tank. 

1. A portable film developing tank comprising: a housing adapted to be filled with developing fluid, mounting means within said housing for rotatably mounting a film cassette, a helical channel within said housing, said helical channel continuously increasing in width from one end to the other in a direction away from said mounting means, holding means attached to said housing near the entrance to said helical channel for holding the end of a film projecting from said cassette, and means for feeding said film from said cassette into said helical channel while the end of said film is held by said holding means such that said film advances in a folded manner within said helical channel.
 2. The portable film developing tank of claim 1 wherein: said mounting means is located toward a center portion of said portable film developing tank and said film is payed out toward the outside of said tank.
 3. The portable film developing tank of claim 1 wherein: said mounting means is located toward an outside periphery of the portable film developing tank for paying out said film toward the center of said tank. 